In the past, various efforts have been made to provide repellent properties to a substrate. For example, U.S. Pat. No. 4,687,707 (=EP-A-0 166 363) describes a low reflectance, transparent material having anti-soiling properties, which comprises a transparent substrate having a coating comprising a thin layer of a condensation product of a fluorine containing silicon compound having a polyfluorinated or perfluorinated carbon chain.
WO 99/03941 relates to a coating material comprising condensates of at least one compound (A) of the general formula RaMZb (a=0 to 3; b=1 to 4; a+b=3, 4), and at least one compound (B) of the general formula R′xMZy (x=1 to 3; y=1 to 3; x+y=3,4), wherein R is a non-hydrolysable organic group, M is an element selected from the main groups III to V or from the subgroups II to IV of the periodic table of elements, Z is a hydrolysable group, and at least one R′ contains a perfluoropolyether structure separated from M by at least two atoms, and at least one R is not equal to at least one R′. The composition is used to provide oleophobic properties to substrates, such as porous polymers.
U.S. Pat. No. 5,739,369 (=EP-A-0 738 771) relates to a water-soluble surface treating agent comprising the reaction product of (A) a fluoroalkyl group-containing alkoxysilane with (B) an amino-group-containing alkoxysilane and optionally further with (C) an alkyl group-containing alkoxysilane. The agent is diluted with water to form a solution for treating glass and other substrates to impart thereto properties, such as water repellency.
U.S. Pat. No. 5,919,886 relates to a fluorine-containing organo-silicon compound useful for obtaining elastomers and to room temperature curable silicon compositions containing the same compound.
U.S. Pat. No. 5,306,758 (=EP-A-0 433 070) describes fluorocarbon based, curable, crosslinkable compositions and coatings prepared therefrom that can be used to form low-surface energy release liners.
U.S. Pat. No. 5,922,787 (=EP-0 797 111) and EP 337 474 relate to a composition containing an alkoxy-silane compound having a perfluoropolyether group. The composition may be used for forming an anti-fouling film.
EP 222 157 discloses a hydrolysable silyl group-containing fluoroolefin copolymer that is obtained by polymerizing a monomeric mixture comprising a fluoroolefin such as tetrafluoroethylene and the like in the presence of a hydrolysable silyl group-containing compound. The copolymer is dissolved in an organic solvent and a curing catalyst is added to obtain a low temperature curable resin composition. The composition is intended for use as a paint for household appliances, for buildings, tiles and precoated metals. Similar compositions are described in JP 11 172200.
U.S. Pat. No. 5,527,931 discloses a condensation product of (i) a fluorochemical oligomer having a hydrophilic group such as carboxylic acid groups and a hydrolysable silyl group and (ii) an alkoxysilane. The condensation product is used for rendering a porous substrate more easy to clean and to render it repellent to water and oil.
WO 96/16630 discloses condensation products of an alkoxy silane and a polymer derived from polymerization of a hydrolysable silyl group-containing monomer, acrylic acid and fluorinated monomer for use in dental applications to reduce adhesion of bacteria and proteinaceous substances.
EP 1 054 047, JP 2000 351941, JP 2001 049173 and JP 2001 049181 describe anti-fouling coatings that are based on a fluoropolymer having silyl groups and an organosilane compound such as for example a tetraalkoxysilane.
Despite the many known fluorochemical compositions to provide repellency properties to a substrate, there continues to be a desire to find further compositions that may have improved initial repellency properties and/or that have improved durability, i.e. the repellency properties last longer even under abrading conditions.
Accordingly, it is desirable to provide a coating composition capable of providing a highly durable water, oil and/or stain repellent coating on a substrate. In particular, it is desirable to provide a durable coating wherein the initial, repellent properties are substantially maintained, even under abrading conditions. Further, the coating compositions preferably can be applied and used in an environmental friendly way and can be produced in a reliable, convenient and cost effective way. Desirably, the coatings also display a good durability against cleaning compositions, in particular, the repellency properties are substantially maintained when the coating has been exposed to a cleaning composition as may be used to clean a treated substrate from time to time. Furthermore, it is desirable to obtain optically clear coatings in particular when transparent substrates such as glass are to be treated with the compositions.